exec: split length -> used_length/max_length
This patch allows us to distinguish between two
length values for each block:
max_length - length of memory block that was allocated
used_length - length of block used by QEMU/guest
Currently, we set used_length - max_length, unconditionally.
Follow-up patches allow used_length <= max_length.
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/exec.c b/exec.c
index a89aa6c..b69216a 100644
--- a/exec.c
+++ b/exec.c
@@ -812,11 +812,11 @@
/* The list is protected by the iothread lock here. */
block = ram_list.mru_block;
- if (block && addr - block->offset < block->length) {
+ if (block && addr - block->offset < block->max_length) {
goto found;
}
QTAILQ_FOREACH(block, &ram_list.blocks, next) {
- if (addr - block->offset < block->length) {
+ if (addr - block->offset < block->max_length) {
goto found;
}
}
@@ -1305,13 +1305,14 @@
/* This assumes the iothread lock is taken here too. */
qemu_mutex_lock_ramlist();
- new_block->offset = find_ram_offset(new_block->length);
+ new_block->offset = find_ram_offset(new_block->max_length);
if (!new_block->host) {
if (xen_enabled()) {
- xen_ram_alloc(new_block->offset, new_block->length, new_block->mr);
+ xen_ram_alloc(new_block->offset, new_block->max_length,
+ new_block->mr);
} else {
- new_block->host = phys_mem_alloc(new_block->length,
+ new_block->host = phys_mem_alloc(new_block->max_length,
&new_block->mr->align);
if (!new_block->host) {
error_setg_errno(errp, errno,
@@ -1320,13 +1321,13 @@
qemu_mutex_unlock_ramlist();
return -1;
}
- memory_try_enable_merging(new_block->host, new_block->length);
+ memory_try_enable_merging(new_block->host, new_block->max_length);
}
}
/* Keep the list sorted from biggest to smallest block. */
QTAILQ_FOREACH(block, &ram_list.blocks, next) {
- if (block->length < new_block->length) {
+ if (block->max_length < new_block->max_length) {
break;
}
}
@@ -1350,14 +1351,15 @@
old_ram_size, new_ram_size);
}
}
- cpu_physical_memory_set_dirty_range(new_block->offset, new_block->length);
+ cpu_physical_memory_set_dirty_range(new_block->offset,
+ new_block->used_length);
- qemu_ram_setup_dump(new_block->host, new_block->length);
- qemu_madvise(new_block->host, new_block->length, QEMU_MADV_HUGEPAGE);
- qemu_madvise(new_block->host, new_block->length, QEMU_MADV_DONTFORK);
+ qemu_ram_setup_dump(new_block->host, new_block->max_length);
+ qemu_madvise(new_block->host, new_block->max_length, QEMU_MADV_HUGEPAGE);
+ qemu_madvise(new_block->host, new_block->max_length, QEMU_MADV_DONTFORK);
if (kvm_enabled()) {
- kvm_setup_guest_memory(new_block->host, new_block->length);
+ kvm_setup_guest_memory(new_block->host, new_block->max_length);
}
return new_block->offset;
@@ -1391,7 +1393,8 @@
size = TARGET_PAGE_ALIGN(size);
new_block = g_malloc0(sizeof(*new_block));
new_block->mr = mr;
- new_block->length = size;
+ new_block->used_length = size;
+ new_block->max_length = size;
new_block->flags = share ? RAM_SHARED : 0;
new_block->host = file_ram_alloc(new_block, size,
mem_path, errp);
@@ -1420,7 +1423,8 @@
size = TARGET_PAGE_ALIGN(size);
new_block = g_malloc0(sizeof(*new_block));
new_block->mr = mr;
- new_block->length = size;
+ new_block->used_length = size;
+ new_block->max_length = max_size;
new_block->fd = -1;
new_block->host = host;
if (host) {
@@ -1475,11 +1479,11 @@
xen_invalidate_map_cache_entry(block->host);
#ifndef _WIN32
} else if (block->fd >= 0) {
- munmap(block->host, block->length);
+ munmap(block->host, block->max_length);
close(block->fd);
#endif
} else {
- qemu_anon_ram_free(block->host, block->length);
+ qemu_anon_ram_free(block->host, block->max_length);
}
g_free(block);
break;
@@ -1499,7 +1503,7 @@
QTAILQ_FOREACH(block, &ram_list.blocks, next) {
offset = addr - block->offset;
- if (offset < block->length) {
+ if (offset < block->max_length) {
vaddr = ramblock_ptr(block, offset);
if (block->flags & RAM_PREALLOC) {
;
@@ -1575,7 +1579,7 @@
return xen_map_cache(addr, 0, 0);
} else if (block->host == NULL) {
block->host =
- xen_map_cache(block->offset, block->length, 1);
+ xen_map_cache(block->offset, block->max_length, 1);
}
}
return ramblock_ptr(block, addr - block->offset);
@@ -1594,9 +1598,9 @@
RAMBlock *block;
QTAILQ_FOREACH(block, &ram_list.blocks, next) {
- if (addr - block->offset < block->length) {
- if (addr - block->offset + *size > block->length)
- *size = block->length - addr + block->offset;
+ if (addr - block->offset < block->max_length) {
+ if (addr - block->offset + *size > block->max_length)
+ *size = block->max_length - addr + block->offset;
return ramblock_ptr(block, addr - block->offset);
}
}
@@ -1619,7 +1623,7 @@
}
block = ram_list.mru_block;
- if (block && block->host && host - block->host < block->length) {
+ if (block && block->host && host - block->host < block->max_length) {
goto found;
}
@@ -1628,7 +1632,7 @@
if (block->host == NULL) {
continue;
}
- if (host - block->host < block->length) {
+ if (host - block->host < block->max_length) {
goto found;
}
}
@@ -2873,7 +2877,7 @@
RAMBlock *block;
QTAILQ_FOREACH(block, &ram_list.blocks, next) {
- func(block->host, block->offset, block->length, opaque);
+ func(block->host, block->offset, block->used_length, opaque);
}
}
#endif
